| 1. |
- Ehrlén, Johan, et al.
(författare)
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Selection on plant optical traits and floral scent : Effects via seed development and antagonistic interactions
- 2012
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Ingår i: Basic and Applied Ecology. - : Elsevier BV. - 1439-1791 .- 1618-0089. ; 13:6, s. 509-515
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Tidskriftsartikel (refereegranskat)abstract
- Evolutionary explanations of plant reproductive traits have usually emphasized optical characteristics of plants and selection mediated by pollinators. In recent years, studies have been broadened by incorporating also interactions with antagonists and by studying plant fragrant cues. Here, we examined if optical and fragrance traits of the perennial herb Primula veris correlated with reproductive success, in terms of fruit and seed set, and with avoidance of seed predators. Selection path analysis showed that both optical and fragrance traits influenced total seed production, and effects occurred both via fruit and seed set and via predator avoidance. In one case the same trait, inflorescence height, influenced total seed production both positively and negatively through effects on different components of fitness. Our results lend support to the notion that selection by mutualists and antagonists simultaneously acts on optical and fragrance traits.
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| 2. |
- von Euler, Tove, 1976-
(författare)
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Environmental heterogeneity, population dynamics and life-history differentiation in Primula farinosa
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Allocation to reproduction is a key life-history trait. Optimal allocation to reproduction depends on environmental conditions because of their effects both on costs and benefits of reproduction and on patterns of growth, fecundity, and mortality. In this thesis, I studied 24 populations of the perennial herb Primula farinosa in the northern part of the Great Alvar on Öland, SE Sweden, and in an experimental garden at Stockholm University to investigate how plant allocation patterns and population dynamics vary along environmental gradients. In the first study, I performed experimental manipulations of reproduction to study costs of reproduction in relation to water availability. In the second study, I performed a demographic survey to investigate the effects of pre-dispersal seed predation on host-plant population dynamics in relation to environmental context. In the third study, I used a common garden experiment to investigate whether environmental variation among natural populations was correlated with genetic differentiation in reproductive effort, and in the fourth study, I performed reciprocal transplantations among four populations to investigate whether genetically based adaptive differentiation among local populations could be detected. The results showed that under natural conditions, plant reproductive costs, intensity of pre-dispersal seed predation, population growth rate and reproductive effort varied with water availability and vegetation height. Costs of reproduction were detected at high and low water availability but not under intermediate soil moisture conditions (paper I). Population dynamics of P. farinosa were affected by environmental conditions both directly, through effects on potential population growth rate (in the absence of seed predation) and indirectly, through effects on seed predation intensity and sensitivity to seed predation (paper II). Among-population genetic differentiation in reproductive allocation was documented in the common-garden experiment (paper III). However, reciprocal transplantations among populations separated by up to 6.2 km provided no evidence of local adaptation to current environmental conditions. Moreover, large differences in the performance of individuals transplanted to different study sites suggest that the study populations display considerable phenotypic plasticity (paper IV). Taken together, the results of these studies suggest that environmental variation has important direct and indirect effects on population dynamics and life history trade-offs in P. farinosa, and that differences in reproductive effort partly reflect genetic differentiation, but that phenotypic variation observed among natural populations does not reflect adaptations to current environmental conditions.
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| 3. |
- von Euler, Tove, 1976-, et al.
(författare)
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Floral display and habitat quality affect cost of reproduction in Primula farinosa
- 2012
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 121:9, s. 1400-1407
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Tidskriftsartikel (refereegranskat)abstract
- Costs of reproduction should depend on resource availability and on reproductive effort, which in turn may depend on traits influencing reproductive success. Therefore, variation in both habitat quality and reproductive traits should be considered when assessing reproductive costs. We investigated the effect of habitat quality and floral display on the costs of reproduction in the perennial herb Primula farinosa. In the study area, P. farinosa occurs in habitats that differ in water availability, which strongly influences plant performance. Furthermore, it displays a scape length dimorphism, with two distinct scape morphs differing in attractiveness to pollinators and reproductive success. To test the hypothesis that the cost of fruit production is higher in the long-scaped than in the short-scaped morph, and depends on water availability, we manipulated reproductive investment in eight P. farinosa populations along a gradient of soil moisture. Fruit set was higher in long-scaped individuals, and prevention of fruit set increased flower production in the following year among long-scaped, but not among short-scaped plants. Furthermore, costs of fruit production were evident at low and high moisture levels but not at intermediate levels. The results demonstrate an association between a genetically determined difference in floral display and cost of reproduction, and suggest that costs of reproduction are non-linearly related to water availability. They thus indicate links between the evolution of plant reproductive traits and plant life histories, and between habitat quality and optimal life history.
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